code: def test_validation_curve():
      acc_train = np.arange(0.1, 1.0, step=0.1)[:, np.newaxis]
      acc_val = acc_train - 0.5
      train_size = np.arange(100, 1000, step=100)
  
      plot.validation_curve(acc_train, acc_val, train_size)
  
imports: from functools import partial
  import sys
  from unittest.mock import Mock
  import numpy
  from matplotlib.testing.decorators import image_comparison
  from sklearn_evaluation import plot
label_desc: Use image node_id 24 for calling a global function with example usage: test_validation_curve() without return types